Structural color is observed in nature and has many characteristics that differ from those of chemical pigments or dyes. Typically color is due to light absorption, but structural color can both refract and reflect light. Reflection is the main mechanism for ordered structural color/photonic crystals, such as those seen in blue butterflies. Structural color can also work by reflective interference in the case of thin film multilayers.
Owing to its unique characteristics, there have been attempts at making artificial structural color through various technological approaches such as colloidal crystallization, dielectric layer stacking, and direct lithographic patterning. The colloidal crystallization technique is used to make a photonic crystal, which blocks a specific wavelength of light in the crystal and therefore displays the corresponding color. Dielectric layer stacking and lithographic patterning of periodic dielectric materials generates structural color by controlling the submicrometer structure of the surface.
Design of structural colored surfaces can provide adaptability or tunability to effect the visual appearance of a surface.